Abstract: A set of instruments for boring of radicular dental canals, in which the diameter D1 of each instrument, measured at the root of the pointed end portion thereof, varies according to a geometrical progression as well as the diameter D2 of each instrument measured at the root of the cutting edges. Hence, the variation is more pronounced for the diameters D2, larger than the diameters D1, than it is for the diameters D1. The conicity of the stem of the instruments increases in this manner from one instrument to another, so as to permit a the dentist to form the radicular canals with a specially funnelled shape which is best suited for some obturations, especially those to be treated with gutta-percha.

Abstract: The end of an instrument for the treatment of dental root-canals is coated with a layer of anti-friction material. The low coefficient of friction of the antifriction material and the fact that it renders the end of the instrument non cutting or non abrasive facilitates greatly the penetration of the instrument in the dental root-canal, especially when the canal is curved, and has the result that the instrument does not bite into the wall of the canal and does not exert thereon an action which is greater on the outside of the curve than on the inside thereof.